The NHLBI Electron Microscopy Core Facility has supported projects using the following techniques in the past year: 1. Chemical fixation, embedding, ultra-thin sectioning and transmission EM digital imaging of tissues and cell culture. 2. EM immunocytochemistry, including immunogold, nanogold with silver enhancement and immunoperoxidase localisation of proteins and other antigens within and on the surface of tissues and cells by pre-embedding techniques. 3. Negative staining of large proteins, polymers and supramolecular structures as well as lipid and membrane vesicles for transmission EM digital imaging. 4. Rotary shadowing of large protein molecules, DNA and other macromolecules. 5. Preparation of platinum replicas of cytoskeletons, partially lysed cells and freeze-fractured/freeze- dried tissues and cells. 6. Chemical fixation, critical point drying, sputter-coating and scanning EM digital imaging of small organisms, organs, tissues and cells, as well as other materials such as artificial matrices. 7. Thawed cryosection immuno labeling technique (also called Tokuyasu method) 8. Immuno correlative light and electron microscopy (CLEM) on Tokuyasu cryosections. 9. Cryo-electron microscopy of vitreous sections (CEMOVIS) to observe biological samples in their most native, fully hydrated state. 10. High pressure freezing (HPF) and freeze substitution (FS) allows improved morphological preservation compared to the conventional preparation. These techniques are available as a service to be performed by the EM Core Staff for the customer or they are available to be learned by users who will be trained to be independent users of the EM Core. In the past year, we have supported 60 projects for 21 principal investigators in the NHLBI/DIR and 18 projects for scientists outside the DIR. We have trained several postdoctoral fellows, students, and contractors in the use of the scanning and transmission electron microscopes and sample preparation techniques.